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dc.contributor.authorSong, Hyon Min
dc.contributor.authorZink, Jeffrey I.
dc.contributor.authorKhashab, Niveen M.
dc.date.accessioned2015-08-03T12:09:25Z
dc.date.available2015-08-03T12:09:25Z
dc.date.issued2014-09-30
dc.identifier.citationSong, H. M., Zink, J. I., & Khashab, N. M. (2014). Engineering the Internal Structure of Magnetic Silica Nanoparticles by Thermal Control. Particle & Particle Systems Characterization, 32(3), 307–312. doi:10.1002/ppsc.201400118
dc.identifier.issn09340866
dc.identifier.doi10.1002/ppsc.201400118
dc.identifier.doi10.1002/ppsc.201570008
dc.identifier.urihttp://hdl.handle.net/10754/563766
dc.description.abstractCalcination of hydrated iron salts in the pores of both spherical and rod-shaped mesoporous silica nanoparticles (NPs) changes the internal structure from an ordered 2D hexagonal structure into a smaller number of large voids in the particles with sizes ranging from large hollow cores down to ten nanometer voids. The voids only form when the heating rate is rapid at a rate of 30 °C min-1. The sizes of the voids are controlled reproducibly by the final calcination temperature; as the temperature is decreased the number of voids decreases as their size increases. The phase of the iron oxide NPs is α-Fe2O3 when annealed at 500 °C, and Fe3O4 when annealed at lower temperatures. The water molecules in the hydrated iron (III) chloride precursor salts appear to play important roles by hydrolyzing Si-O-Si bonding, and the resulting silanol is mobile enough to affect the reconstruction into the framed hollow structures at high temperature. Along with hexahydrates, trivalent Fe3+ ions are assumed to contribute to the structure disruption of mesoporous silica by replacing tetrahedral Si4+ ions and making Fe-O-Si bonding. Volume fraction tomography images generated from transmission electron microscopy (TEM) images enable precise visualization of the structures. These results provide a controllable method of engineering the internal shapes in silica matrices containing superparamagnetic NPs.
dc.description.sponsorshipThe authors gratefully acknowledge support from King Abdullah University of Science and Technology (KAUST) and the NSF grant DBI-1266377.
dc.publisherWiley-VCH Verlag
dc.subjectIron oxide nanoparticles
dc.subjectMesoporous silica
dc.subjectStructure engineering
dc.subjectSuperparamagnetic nanoparticles
dc.subjectThermal control
dc.titleEngineering the internal structure of magnetic silica nanoparticles by thermal control
dc.typeArticle
dc.contributor.departmentAdvanced Membranes and Porous Materials Research Center
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentChemical Science Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.contributor.departmentSmart Hybrid Materials (SHMs) lab
dc.identifier.journalParticle and Particle Systems Characterization
dc.contributor.institutionDepartment of Chemistry and Biochemistry, University of CaliforniaLos Angeles, CA, United States
dc.contributor.institutionDepartment of Chemistry, Dong-A UniversityBusan Saha-gu, South Korea
kaust.personKhashab, Niveen M.
kaust.personSong, Hyon Min
dc.date.published-online2014-09-30
dc.date.published-print2015-03


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